Field of Invention
The present invention relates to the field of micro/nano testing, and more particularly to a contact trigger three-dimensional probe applied to micro/nano coordinate measuring machines (CM Ms) for sensing three-dimensional topography of an object.
Description of Related Arts
In recent years, the rapid development of micro electronic techniques has headed to a miniaturized revolution. In particularly, the development of the processing technique of MEMS (micro electro mechanical system) has brought in various micro-devices including MEMS products such as micro-gears, micro-holes, micro- micro-nozzles and micro-steps. These micro-devices have a micro-nanometer level machining precision, so it is necessary to develop high precision detection method and technical means for precisely measuring the micro-devices. Thus, the relevant agencies of various countries are devoted to researching coordinate measuring machine with nanometer precision.
The probe is a core component for the CMMs. The probe's measurement accuracy determines the overall measurement accuracy of the CMMs. The probe is classified in a contact type and a non-contact type. The contact type probe can be used for detecting the work pieces that the non-contact probe is not capable of detecting, such as the work pieces having characteristics such as a slope, steps, deep holes, arc and etc.
The sensing principle of the contact probes in the conventional arts mainly comprise atomic force, capacitive, fiber optic, DVD pick-up head, piezoresistor and confocal and etc. Due to requiring two to four high precision sensors, the conventional probes have problems of complex structures, installation difficulty and high costs. For instance, Eindhoven University of Netherlands developed three-dimensional micro-contact sensor probe based on strain gauge, wherein the strain gauge, circuit and the elastic components performs processes of precipitation, plate making, etching and other processes together to make the overall structure of the probe. Changes of force and displacement in all directions are detected by the strain gauge mounted on the sensitive beam. The volume is small, but the sensitivity and precision of the strain gauge are relatively low. Furthermore, the probe adopts triangular topology structure and the decoupling thereof is complicated. Swiss Federal Metrology Bureau METAS developed an electromagnetic based micro-contact probe, wherein the probe is leaf spring om on three directions, and the detections of each direction are achieved by inductance. The detecting forces are uniform on three directions, and the probe is mainly made of aluminum. The electromagnetic probe has a wide measuring range, a high sensitivity on lateral detection, a small contact force, but the structure thereof is very complex, and the installation and adjustment is difficult, and decoupling of the triangular suspension structure is complex.